“Some of the affected users were unable to access their accounts, instead seeing an outdated ‘scheduled maintenance’ page, which was a confusing and incorrect message (this has since been corrected and updated),” Mayer wrote. “Further, messages sent to those accounts during this time were not delivered, but held in a queue.”

Mayer did not say how many users the issue affected, but revealed that the hardware problem affected a storage system that serves 1% of Yahoo’s users. She added that access has been restored – as of Friday – to almost everyone on Yahoo Mail, although specific issues were still ironed out including IMAP access and a full restoration of inboxes’ state – “for example which folders messages were placed in, which messages were starred, etc.” According to the CEO, Yahoo Mail’s uptime is “well above” 99.9% including the extended outage. Mayer admitted that Yahoo “really let you down this week,” promising to do better in the future.

Mayer wrote on her personal Tumblr blog on Wednesday, during the Yahoo Mail crisis, a short post titled “Yahoo Mail restored” that contained a link to a Yahoo Help document. The company was mostly uncommunicative with affected users, and was late to acknowledge and detail the issues that affected Yahoo Mail.

Yahoo Mail saw two redesigns in the past year, although many Yahoo Mail users voiced their concerns online about some of the user interface changes. However, reports claimed that Yahoo has mostly ignored the feedback received instead of properly addressing it, with an exec joking that Yahoo Mail users would have to be “kicked hard” in a certain body part to leave.